In accordance with a rapid spread of information relevant apparatuses and communication apparatuses such as a personal computer, a video camera and a portable telephone in recent years, the development of a battery to be utilized as a power source thereof has been emphasized. The development of a high-output and high-capacity battery for an electric automobile or a hybrid automobile has been advanced also in the automobile industry. A lithium battery has presently drawn attention from the viewpoint of a high energy density among various kinds of batteries.
Liquid electrolyte containing a flammable organic solvent is used for a presently commercialized lithium battery, so that the installation of a safety device for restraining temperature rise during a short circuit and the structure for preventing the short circuit are necessary therefor. On the contrary, a lithium battery, namely a battery all-solidified by replacing the liquid electrolyte with a solid electrolyte layer, is conceived to intend the simplification of the safety device and be excellent in production cost and productivity for the reason that the flammable organic solvent is not used in the battery. A solid electrolyte material is usually used for an all solid lithium battery.
Patent Literature 1 discloses a sulfide solid electrolyte material wherein the sulfide solid electrolyte material is a glass ceramics comprising: an ion conductor having Li, A (A represents at least a kind of P, Si, Ge, Al or B), and S, LiX (X represents halogen), and ortho-oxo acid lithium; wherein the sulfide solid electrolyte material has a peak at a position of 2θ=20.2°, 23.6°; and a proportion of the ortho-oxo acid lithium is less than 20 mol %. Incidentally, Patent Literature 1 discloses Li3PS4 as the ion conductor and Li3PO4 as the ortho-oxo acid lithium.